In the solid waste industry typically permitted active landfills are used for the disposal of solid waste. The portion of the landfill where waste is actually being unloaded, placed, and compacted is called the “working face” of the landfill. This working face is where waste is placed and compacted by vehicles. Generally these vehicles are track or cleated/chopper wheel driven. These vehicles not only position the waste for efficient air space utilization of land fill capacity but most importantly compact the waste for maximum utilization of the permitted volume. Sub-portions of this permitted volume are most frequently called a “cell” by field personnel.
One of the side effects of this disposal and compacting process is the generation of “leachate”. Leachate is the liquid that is hauled in with the waste or rainwater that has fallen on the site, that has come in contact with solid waste. By regulation most landfills are required to collect, treat, and/or dispose of this liquid. This is an added expense to landfill operations. One very effective means to dispose of this liquid is to redistribute leachate on the working face with the new incoming waste stream. Experience has shown that the compaction rate is improved if the incoming waste stream is damp or moist. This dampness will increase the compaction of waste into a smaller volume, thus using less volume of the cell per ton of waste. Furthermore, with this added moisture a greater waste compaction is achieved with less vehicle time, thus requiring fewer passes of the compaction equipment back and forth across the working face. This translates to greater productivity of these vehicles and the use of less fuel per ton of waste compacted.
Landfill leachate is created when precipitation percolates down through the waste deposited at a landfill. Landfill leachate is very high in organics, nitrogen, metals and other toxic materials and is a significant environmental and health concern if released into the environment untreated.
Prior art techniques for leachate disposal on the working face have generally been confined to the use of spray nozzles and portable pumps. This technique frequently requires the presence of assigned personnel to control and direct the leachate distribution. Prior art also uses a pressured nozzle (much like a garden or small fire hose) that shoots the liquid leachate into the air in order to get it to the waste being compacted on the working face. Because of the nozzle and pressure pump there is a fairly solid stream of liquid being propelled from it, and the nozzle also causes some of the liquid (leachate) to be turned into a vapor or mist which potentially could be carried by a breeze where it can settle on nearby earth or vegetation. Furthermore, this mist could cause potential health hazard to personnel working nearby.
Prior art techniques limit the area that can be covered by the sprayed leachate to that reached by the spraying radius of the nozzle. This will cause an uneven distribution of the leachate over the working face waste leaving dry areas and over saturated areas. This would obviously make the compaction uneven and sporadic.
The intended purpose of the present invention is to provide a means to spread a relatively even distribution of liquid (typically site collected leachate) over the entire working face of a solid waste disposal site to improve compaction as well as other benefits.
The present invention would substantially minimize or almost eliminate the misting of the leachate and cause the leachate to be much more evenly distributed over the work surface. It will also add additional weight to the working face vehicle which enhances the compaction rate. In addition, keeping the compactor wheels and cleats as well as the tracks of the dozer damp or wet with leachate will greatly reduce clogging and improve the effectiveness of the compacting process.
Another benefit of the present invention is to minimize fire hazards on the working face waste. The present invention will also minimize the spread rate of any fire if it should occur. Moist or damp waste will obviously not burn as rapidly as dry waste.
An additional benefit of the present invention is the accelerated rate of decomposition of the compacted waste. This will lead to a more rapid generation of methane gas which could be used as a potential energy source.